Flags (by name of flag bearing entity)

In bold, stamps issued by the entity which it belongs or is most
connected to. This allows to separate “authoritative” (or at least
well informed) depictions from casual ones, and also to emphasize how much a
flag is popular in foreign stamps.

In italics, stamps showing one single flag, be it as the main design
element, or as a detail — thus those in roman style show more than one one
flag.